BIOPSY TISSUE SAMPLES

Technical Field

[0001] The present invention generally relates to supports for handling and embedding tissue samples for pathological analysis and, more particularly, to microtome sectionable supports which can receive one or more tissue samples and a support frame having a tissue immobilizing separable lid.

Background

[0002] To accurately diagnose various tissue diseases and conditions, medical personnel must remove one or more samples of tissue from the body of a patient. This process of harvesting tissue from the body is known as a biopsy. Once the tissue sample or samples are removed and sent to a pathology laboratory, the tissue will go through a series of procedures performed by a histotechnician and, ultimately, a pathologist, in order to diagnose one or more conditions associated with the tissue. The present invention generally relates to those procedures that are normally performed by the histotechnician to prepare the tissue sample or samples into slides that may be analyzed under a microscope by the pathologist.

[0003] Although the singular term "sample" is used throughout this specification, it should be understood that this term likewise encompasses plural "samples" as well. Once a tissue sample is removed from the body of a patient, it is typically placed into a specimen container containing a tissue fixative solution and then the container is transported to a pathology laboratory. The tissue will undergo a process known as "grossing-in" in the pathology lab during which a histotechnician will retrieve the tissue sample from the container, typically cut the tissue into appropriate sizes for tissue processing, place individual samples into the appropriate sized small plastic tissue cassettes, and assign tracking numbers to each cassette. These tracking numbers are then logged into a tracking system used in the laboratory. For the smallest tissue samples, which may only be scrapings, the cassette includes fine mesh openings on the sides and bottoms. In other situations involving very small tissue samples, the samples are placed into a bag that resembles a tea bag that prevents the smallest tissue samples from escaping. Larger tissue samples are placed into cassettes having somewhat larger slotted openings which are nevertheless smaller than the tissue sample inside the cassette.

[0004] The cassettes are then placed into a stainless steel perforated basket and run through a tissue processing machine, often overnight. This machine uses a combination of vacuum, heat, and chemicals to remove the interstitial fluids within the tissue. Once the fluids have been removed from the tissue samples, the processing machine immerses the tissues samples in a bath of a hardenable material such as molten paraffin (i.e., a form of wax) so that the interstices in the tissue are replaced with paraffin. The histotechnician then removes the basket from the machine and removes the individual tissue cassettes. In a conventional procedure practiced for many years, the histotechnician individually removes the tissue sample from each cassette. The histotechnician must carefully orient the tissue sample, based on tissue type, into a stainless steel base mold that is roughly the size of the tissue cassette and is partially filled with molten paraffin. The tissue sample must be manually held, typically using forceps, against the bottom of the mold. If it is not, this could compromise the ability to make proper slices of the tissue sample later in a microtome. The molten paraffin is then rapidly cooled on a refrigerated plate, which may be a thermal electric cooler (TEC), to partially solidify the paraffin thereby holding the tissue sample in the proper orientation against the bottom of the mold.

[0005] The cassette is then placed on top of the base mold and an embedding material, which is also typically paraffin wax, is poured through the opened top of the cassette into the base mold. The cassette changes its function at this point in the procedure from a tissue holding component to a fixture type device for mounting in the microtome and making shavings or slices from the solidified paraffin in the microtome. The base mold is chilled until all of the molten paraffin has hardened and the histotechnician removes the stainless steel base mold from the block of embedded paraffin. The tissue sample is thus embedded within a rectangular block of hard paraffin with a plastic tissue cassette on the opposite side. As mentioned, the cassette may then be used as a holder or fixture in the chuck of the microtome. As with the tissue processing machine, the embedding process is accomplished in a batch fashion during which an average histotechnician may embed approximately 40 to 60 cassettes per hour. [0006] The blocks of hardened paraffin containing the embedded tissue samples are then ready to be sliced into extremely thin sections for placement on a microscope slide. The histotechnician mounts the embedded tissue block in a chuck on the microtome that is sized to accept the side of the block that has the embedded plastic cassette. The histotechnician can then begin slicing the paraffin block which has the tissue sample embedded opposite to the plastic cassette surface. This yields a ribbon of individual slices of the tissue embedded in the hardened paraffin. The action of the microtome causes the individual slices to stick together when done properly and, subsequently, these very thin ribbons of slices are floated into a water bath and a glass slide is carefully placed underneath the slice. The slice, with the thin sectioned tissue sample embedded therein, is then adhered to the top of the slide.

[0007] When the histotechnician has enough slides from the tissue sample, the slides are placed into an automatic staining machine. The staining machine goes through a series of infiltrating steps to stain the different tissue and cells of the slide different colors. This helps the pathologist identify different structures and makes it easier to find any abnormalities in the tissue. After the staining procedure is complete, the slides are cover slipped and prepared for the pathologist to place under a microscope for analysis.

[0008] Based on the summary of the procedure provided above, it will be appreciated that conventional tissue sample handling and processing is a very labor-intensive process involving several manual steps performed by a histotechnician. Thus, repetitive stress injuries such as carpal tunnel syndrome are prevalent. This is especially true with the tissue sample embedding process. These multiple manual operations and repeated tissue handling increase the likelihood of human error and, moreover, require highly trained and skilled histotechnicians to ensure that the tissue samples ultimately adhered to the slides for analysis by the pathologist are in an optimum condition and orientation to make accurate diagnoses.

[0009] U.S. Patent Nos. 5,817,032 (the Ό32 patent), 7, 156,814,

7, 179,424, 7,722,810, 7,776,274 and 8,383,067 disclose various improvements to this area of technology, including new manners of holding tissue samples during the grossing in, embedding, and microtome or slicing procedures. The disclosures of U.S. Patent Nos. 5,817,032 (the Ό32 patent), 7, 156,814, 7, 179,424, 7,722,810, 7,776,274 and 8,383,067 are hereby fully incorporated by reference herein. For example, the Ό32 patent relates to a tissue trapping and supporting device, which may be a cassette, and which may be

successfully sectioned using a microtome. When such a cassette is used, the tissue sample is immobilized within the cassette and subjected to the process for replacing tissue fluids with paraffin. Then, the tissue sample and the cassette are sliced at the same time for later mounting on microscope slides. Because the tissue sample is never removed from the cassette from the time it is processed in the tissue processing machine to the time that it is cut or sliced with the microtome, a significant amount of handling time is saved. Moreover, the chance for human error or tissue loss is significantly reduced due to the elimination of separate tissue handling steps. The '032 patent and the above- incorporated published applications also generally disclose further

improvements that help to automate the overall process and, in conjunction with the novel tissue supports (e.g., cassettes), can even further reduce the handling steps during the entire procedure and make the procedure more reliable.

[0010] Various drawbacks of current procedures and limits on innovation exist. For instance, improvements to the outer form of the cassette and frame are bounded by existing limits of histopathology lab equipment such as tissue processing retorts, and "input devices" for tissue processors, embedding stations, and microtomes. Many of these processes are integrated with systems and machines for automation of the steps and robotic handling there between further limiting the potential for innovation. Additionally, costs for materials have been rising in recent years, especially for the fluoropolymer (FEP/PFA) sectionable plastics useful in sectionable cassettes. Each cassette is essentially consumed by the sectioning procedure, which adds to the cost of the pathology procedure. Further, because the sectionable FEP/PFA material is not rigid, it is challenging to manufacture a secure lid from this material that will not dimensionally distort during transit and storage. Currently, frames and cassette baskets are shipped to the customer in separate boxes and must be assembled by the user. With increased scrutiny on healthcare costs due to governmental and competitive forces, the need for a lower-cost device and ways to reduce labor are necessary.

[0011] In spite of the various advances made in this field, there is an increasing need for additional improvements related to increased production capability and more consistent quality of embedded tissue samples and resulting slices or ribbons of embedded tissue that will be subject to diagnosis. This can be especially important when handling smaller tissue sample sizes, although the improvements to be disclosed herein are applicable to all tissue sample sizes.

Summary

[0012] In accordance with one embodiment, a histologic tissue sample support device includes a tissue cassette having a recess including at least one side wall and a bottom wall, the tissue cassette formed of material that can be successfully sectioned in a microtome and is resistant to degradation from solvents and chemicals used to fix, process and stain tissue. The device further includes a frame including a peripheral portion and a bottom edge, the tissue cassette being movably coupled to the frame, and a lid separably coupled to the peripheral portion of the frame. It will be appreciated that the lid may be coupled to the peripheral portion in a frangible manner or in any other separable manner. When the lid is separated from the peripheral portion, the lid and the tissue cassette are capable of moving from a first position to a second position with respect to the frame, and in the second position the bottom wall and at least a portion of the side wall extend beyond the bottom edge of the frame for sectioning in the microtome.

[0013] In accordance with another embodiment, a histologic tissue sample support device includes a tissue cassette having a recess including at least one side wall and a bottom wall, the tissue cassette formed of material that can be successfully sectioned in a microtome and is resistant to

degradation from solvents and chemicals used to fix, process and stain tissue. The device further includes a frame including a peripheral portion and a bottom edge, the tissue cassette being movably coupled to the frame, a microtome sectionable, resilient structure being configured to engage and retain tissue in place during processing and embedding, and a lid separably coupled to the peripheral portion of the frame and coupled to the resilient structure, the lid being used to compress the resilient structure against the tissue. The resilient structure is capable of successful sectioning in the microtome and porous to allow infiltration of the solvents and chemicals used to fix, process and stain tissue, and of embedding material used to embed the tissue while the tissue is retained by the resilient structure in the recess. When the lid is separated from the peripheral portion, the lid and the tissue cassette are capable of moving from a first position to a second position with respect to the frame, and in the second position the bottom wall, at least a portion of the side wall, and at least a portion of the resilient structure extend beyond the bottom edge of the frame for sectioning in the microtome.

[0014] In use, a method of preparing one or more biopsy tissue samples for histological examination using a histologic tissue sample support device, the support device including a microtome sectionable tissue cassette, a frame including a peripheral portion, and a lid separably coupled to the peripheral portion of the frame includes positioning a tissue sample in the tissue cassette, closing the peripheral portion of the frame and the lid when the tissue cassette is in a first position relative to the frame, separating the lid from the peripheral portion of the frame, and moving the lid and the tissue cassette into a second position relative to the frame where a portion of the tissue cassette extends beyond an edge of the frame for sectioning in the microtome.

[0015] In accordance with another embodiment, an apparatus for holding a histologic tissue sample while sectioning the tissue sample in a microtome includes a tissue cassette having a recess including at least one side wall and a bottom wall, the tissue cassette being configured to hold the tissue sample, being formed of a first material that can be successfully sectioned in a microtome, and being resistant to degradation from solvents and chemicals used to fix and process the tissue sample during a histologic procedure. The apparatus further includes a frame having a peripheral portion and a lid, the frame being formed from a second material different from the first material and being formed integrally with the tissue cassette, and the lid being separably coupled to the peripheral portion.

[0016] In use, a method for manufacturing an apparatus for holding a histologic tissue sample while sectioning the tissue sample in a microtome includes molding a tissue cassette having a recess including at least one side wall and a bottom wall, the tissue cassette being formed of a first material that can be successfully sectioned in a microtome, said tissue cassette further being resistant to degradation from solvents and chemicals used to fix and process the tissue sample during a histologic procedure, and molding a frame such that the frame is integrally coupled with the tissue cassette, the frame having a peripheral portion, being formed from a second material different from the first material, and including a lid separably coupled to the peripheral portion.

[0017] Embodiments of the invention further provide histologic tissue sample support devices comprising a tissue cassette having a recess including at least one side wall and a bottom wall. The tissue cassette is formed of material that can be successfully sectioned in a microtome and is resistant to degradation from solvents and chemicals used to fix, process and stain tissue. A frame includes a bottom edge, the tissue cassette being movably coupled to the frame. A lid is coupled to the frame wherein the lid and the tissue cassette are capable of moving from a first position to a second position with respect to the frame, and in the second position the bottom wall and at least a portion of the side wall extend beyond the bottom edge of the frame for sectioning in the microtome.

[0018] In additional or alternative aspects, the lid is coupled to the frame with a hinge. The cassette is coupled to the frame with at least one breakaway connection. The lid is movable from a closed position to an open position and is capable of latching to the tissue cassette in the closed position. The cassette, lid and frame may be molded from a single material. The cassette and frame may alternatively be formed using other techniques such as by being co-molded or insert molded from different materials.

[0019] A method is provided for preparing one or more biopsy tissue samples for histological examination using a histologic tissue sample support device, the support device including a microtome sectionable tissue cassette, a frame, and a lid coupled to the frame. The method comprises positioning a tissue sample in the tissue cassette, closing the lid when the tissue cassette is in a first position relative to the frame and moving the lid and the tissue cassette into a second position relative to the frame where a portion of the tissue cassette extends beyond an edge of the frame for sectioning in the microtome.

[0020] The method may further comprise subjecting the tissue cassette and the tissue sample to a process that replaces fluid in the tissue sample with a hardenable material before or after moving the lid and the tissue cassette into the second position, embedding the tissue cassette and the tissue sample in an embedding material, hardening the embedding material into a block, and slicing the block with a microtome into thin slices of the embedding material, the tissue cassette, and the tissue sample. The method may further comprise after hardening the embedding material into a block, positioning the histologic tissue sample support device in a microtome and latching the lid to the tissue cassette.

[0021] Various additional features and advantages of the invention will become more apparent to those of ordinary skill in the art upon review of the following detailed description of the illustrative embodiments taken in conjunction with the accompanying drawings.

Brief Description of the Drawings

[0022] FIG. 1 is a perspective view of an assembly according to one embodiment.

[0023] FIG. 2 is a top view of the assembly of FIG. 1 showing the tissue cassette and the frame in the open position ready to accept tissue in the tissue cassette.

[0024] FIG. 3A is a cross sectional view of the assembly of FIG. 1 taken generally along line 3A-3A of FIG. 2 showing the tissue cassette and the frame in the open position ready to accept tissue in the tissue cassette.

[0025] FIG. 3B is a cross sectional view of the assembly of FIG. 1 taken generally along line 3A-3A of FIG. 2 showing the peripheral portion of the frame in the closed position.

[0026] FIG. 3C is a cross sectional view of a portion of the assembly of FIG. 1 taken generally along line 3A-3A of FIG. 2 showing the assembly in a staged position where the lid is separated from the peripheral portion of the frame and the tissue and a portion of the tissue cassette are ready to be sectioned in a microtome.

[0027] FIG. 3D is a cross sectional view of a portion of the assembly of FIG. 1 taken generally along line 3A-3A of FIG. 2 showing the tissue cassette embedded in paraffin wax.

[0028] FIG. 4 is a perspective view of an assembly according to one embodiment positioned in a microtome.

[0029] FIG. 5 is a plan view of a sample wax slice prepared using a method according to one embodiment.

[0030] FIG. 6 is a plan view of a sample wax slice prepared using a method according to one embodiment. [0031] FIG. 7 is a perspective view of another embodiment illustrating an integrally formed cassette and frame structure.

[0032] FIG. 8 is a perspective view of the structure illustrated in FIG. 7, but cross sectioned generally along a central lengthwise axis thereof with the lid in a closed position.

[0033] FIG. 9 is a top view of the structure illustrated in FIG. 7 with the lid in an open position.

[0034] FIGS. 10 and 10B are respective cross sectional views (taken along line 10A-10A of FIG. 9) of the structure illustrated in FIG. 9, with FIG. 10A showing the lid in an open position and FIG. 10B illustrating the lid in a closed position.

[0035] FIG. 10C is a cross sectional view similar to FIG. 10B, but illustrating the cassette portion being staged downwardly into a mold.

[0036] FIG. 10D is a cross sectional view similar to FIG. 10C, but illustrating the integrated and staged structure with the microtome sectionable cassette portion and tissue sample embedded in a block of embedding material, such as paraffin.

[0037] FIG. 1 1 A is a perspective view which has been cross sectioned to illustrate additional details of the integrated cassette and frame structure of this embodiment.

[0038] FIG. 1 1 B is a cross sectional view similar to FIG. 1 1 A, but illustrating the lid of the structure in a closed position.

[0039] FIG. 1 1 C is a cross sectional view similar to FIG. 1 1 B, but illustrating the cassette portion in the staged position.

[0040] FIG. 12A is another cross sectional view of the integrated cassette and frame structure of this embodiment, illustrating additional details.

[0041] FIG. 12B is a cross sectional view similar to FIG. 12A, but illustrating the cassette portion in a staged position.

[0042] FIG. 13 is a perspective view of another embodiment, illustrating an integrated cassette and frame structure with the lid of the cassette portion in an open position.

[0043] FIG. 14 is a cross sectional view (taken along line 14-14 of FIG. 13) of the integrated cassette and frame structure from FIG. 13, but illustrating the lid in a closed position. [0044] FIG. 15 is a perspective view of another embodiment, illustrating an integrated cassette and frame structure with the lid of the cassette portion in an open position.

[0045] FIG. 16A is a cross sectional view (taken along line 16-16 of FIG. 15) of the integrated cassette and frame structure from FIG. 15, but illustrating the lid in a closed position.

[0046] FIG. 16B is a cross sectional view similar to FIG. 16A, but illustrating the lid structure engaging a tissue sample within the cassette portion.

[0047] FIG. 17 is a perspective view of another embodiment illustrating an integrated cassette and frame structure, with the lid portion shown in an open position.

[0048] FIG. 18 is a top view illustrating the integrated cassette and frame structure of FIG. 17, again with the lid portion shown in an open position.

[0049] FIG. 19A is a cross sectional view taken generally along line 19A- 19A of FIG. 18.

[0050] FIG. 19B is a cross sectional view similar to FIG. 19A, but illustrating the lid portion in a closed position.

[0051] FIG. 19C is a cross sectional view similar to FIG. 19B, but illustrating the lid portion compressed or moved downwardly against a tissue sample within the cassette body, and illustrating the cassette staged

downwardly with respect to the frame and into a mold.

[0052] FIG. 20A is a perspective, enlarged view of the integrated cassette and frame structure of FIG. 17, and illustrating additional details.

[0053] FIG. 20B is a perspective view similar to FIG. 20A, but illustrating the lid portion in a closed position.

[0054] FIG. 20C is a perspective view similar to FIG. 20B, but illustrating the cassette staged or moved downwardly with respect to the frame into a second, staged position.

[0055] FIG. 21 is a top view of another embodiment illustrating an assembly comprised of an integrated cassette and frame structure.

[0056] FIG. 22A is a partially fragmented cross sectional view of the structure shown in FIG. 21 .

[0057] FIG. 22B is a cross sectioned view of the structure shown in FIG. 22A, but illustrating the lid in a closed position. [0058] FIG. 22C is a perspective view similar to FIG. 22B, but illustrating the cassette staged to a second position within the frame.

[0059] FIGS. 23A and 23B respectively show alternative embodiments of the resilient tissue engaging structure, or fingers, used for holding tissue against a bottom wall of the cassette.

[0060] FIG. 24A is a cross sectional view of the structure shown with the cassette in the process of being moved or staged between the first and second positions, with the cross section taken transverse to a lengthwise dimension of the frame and cassette.

[0061] FIG. 24B is a cross sectional view similar to FIG. 24A, but illustrating the cassette staged completely into the second position.

Detailed Description

[0062] Referring first to FIGS. 1 and 2, an assembly 10 constructed in accordance with an illustrative embodiment of the invention is shown.

Assembly 10 includes of a tissue sample cassette 12 carried within a frame 14, which includes a peripheral portion 16. A lid 18 is separably coupled to peripheral portion 16. Peripheral portion 16 generally includes an interior defined between surrounding walls 16a, 16b, 16c, 16d, and lid 18 is sized and configured to fit in the interior and be separably coupled to at least one of the surrounding walls 16a, 16b, 16c, 16d. The frame 14 generally includes an interior defined between surrounding outer walls 14a, 14b, 14c, 14d and the cassette 12 is sized and configured to frictionally or "snap" fit and move within the interior between at least first and second positions, again, as generally discussed in the above-incorporated patent and patent applications and for the same purposes. The first position is shown in FIG. 3B, while the second position is shown in FIG. 3C in which the lower portion of the cassette 12 is exposed below the bottom of the frame 14 for allowing cassette 12 and tissue sample to be sectioned in a microtome while the frame 14 is held in the microtome chuck.

[0063] The connection of the tissue cassette 12 to the frame 14 may be accomplished in many different manners, such as any of the manners described in the above-incorporated patent and patent applications. In the illustrative embodiment, cassette 12 includes cassette retention tabs 20 that are frictionally secured in retention slots 40 of frame 14. The friction fit between the tabs 20 and the slots 40 prevents unwanted movement of the cassette 12 between the first and second positions. Slots 40 are tapered such that slots 40 are narrower at the bottom than at the top. In this regard, the force required to move the cassette retention tabs 20 to the second position is less than the force required to move the tabs 20 to the first position. It will be appreciated that cassette 12 may be configured in any suitable manner as a tissue support and frame 14 may be configured in any suitable manner. Any of the configurations, features, characteristics and materials disclosed for the tissue supports (e.g., cassettes) and frames in the above-incorporated patent and patent applications may be employed for cassette 12 and frame 14. In the embodiment shown, cassette 12 is porous and is releasably retained in frame 14 and frame 14 is further configured to be releasably secured within a microtome chuck (shown in FIG. 4). The general procedure for processing, embedding, and sectioning is discussed in the above-incorporated patent and patent applications.

[0064] Now referring to FIGS. 2 and 3A, the connections between frame 14, peripheral portion 16, and lid 18 are shown in more detail. Peripheral portion 16 is coupled to wall 14a of frame 14 by a frangible hinge 22.

Peripheral portion 16 snap fits into a closed position through the engagement of latches 24, 26, 28 with frame 14 as shown in FIG. 3B. Latches 24, 26 are positioned on outer wall 16a of peripheral portion 16 and engage with openings 30, 32 in wall 14a of frame 14 respectively. Latch 28 is positioned on wall 16c of peripheral portion 16 and engages with an outer flange 34 of wall 14c of frame 14. Lid 18 is separably coupled to peripheral portion 16 through breakaway connections 36 on surrounding walls 16a, 16b, 16c, 16d. Lid 18 is sized and configured to frictionally or "snap" fit and move within the interior of frame 14 between at least first and second positions, as shown best in FIGS. 3B and 3C. More particularly, lid 18 includes lid retention tabs 38 on each of the four corners of lid 18. Retention tabs 38 are configured to engage with retention slots 40 of frame 14, which are on each of the four corners of frame 14. Lid 18 carries a resilient structure 42 on the central portion of lid 18, which may act as a break-away staging central section of lid 18 to which resilient structure 42 is attached.

[0065] Resilient structure 42 is a compliant structure that holds the tissue in the desired orientation without creating an artifact impression on the tissue sample 44 during processing. As shown in FIG. 3A, one or more tissue samples 44 may be placed in cassette 12 that defines a recess or interior area surrounded by at least one sidewall 12a and including a bottom wall 12b.

Although a rectangular recess is shown, it will be appreciated that any other shape, such as cylindrical or shapes with troughs or alignment features for the tissue sample 44, may be used instead.

[0066] The porosity of resilient structure 42 allows infiltration of the solvents and chemicals used to fix, process, and stain tissue, and of embedding material used to embed the tissue while the tissue is retained by resilient structure 42. Resilient structure 42 has a thickness that is compressible and configured to engage and retain tissue in place during processing and embedding. Further, resilient structure 42 is capable of successful sectioning in the microtome after having its interstices or pores filled with liquefied embedding material which subsequently hardens. Resilient structure 42 may, for example, be an open cell foam material, such as a foam including at least one of a polyether or a polyurethane and which may be a fully reticulated foam. Here, "fully reticulated" means that at least substantially all cells of the foam are open. The open cells help ensure full infiltration and eventual draining of the fluids used during processing and embedding procedures. Resilient structure 42 may further be a gel, sectionable plastic, polyesters, alginates, or other materials that may be infiltrated with the embedding material and successfully sectioned in a microtome without adverse effects on the resulting ribbon of tissue and embedding material.

[0067] With reference now to FIG. 3B, assembly 10 is shown with peripheral portion 16 in the closed position and where cassette 12 and lid 18 are in a first position. Once the tissue is loaded in the interior or recess of cassette 12, peripheral portion 16 may be rotated to the closed position. As peripheral portion 16 is moved from the open position to the closed position, frangible hinge 22 severs. Once hinge 22 is severed, peripheral portion 16 may continue to rotate until latches 24, 26, 28 engage with openings 30, 32 and outer flange 34 of frame 14, securely locking peripheral portion 16 to frame 14. With peripheral portion 16 in the closed position, resilient structure 42 biases the tissue sample 44 towards bottom wall 12b of cassette 12. With peripheral portion 16 securely closed on frame 14, cassette 12 is trapped inside retention slots 40 and cannot become dislodged from frame 14. Lid retention tabs 38 are in alignment with the wider top portion of retention slots 40 of frame 14. Alternatively, in this position, lid retention tabs 38 may be located within a top portion of retention slots 40 and align with corresponding cassette retention tabs 20 when the lid 18 is closed.

[0068] As further shown in FIG. 3B, when lid 18 is closed, the resilient structure 42 presses against tissue sample 44 and deforms three dimensionally around tissue sample 44 creating three dimensional spaces around tissue sample 44 and essentially immobilizing tissue sample 44 during the tissue processing and embedding procedures. This also ensures that the tissue sample 44 is held flat against bottom wall 12b of cassette 12 such that when microtome slices are made, complete and continuous sections of tissue sample 44 may be formed generally as shown in FIG. 5. Once all of sample 44 has been sliced, the next slice would contain only resilient structure 42 and paraffin wax 50, as shown in FIG. 6. One specific type of foam structure suitable for the resilient structure 42 has a pore size of 50-60 ppi (pores per inch), with each pore having a diameter of between about 0.017 inch and 0.20 inch. The foam structure is fully reticulated with a compression force deflection at 20% deflection of 0.55 lbs/in ² and a density of 1.4 lbs/ft ³ . The foam material may be obtained from Crest Foam of Moonachie, New Jersey under the name T-50. This is a polyether/polyurethane foam and operates well with a thickness of 0.06 inch to 0.10 inch with a 0.075 inch thickness being a practical

manufacturing example. The foam should be constructed so as to shed or release processing fluid after each reagent cycle of a tissue processing machine. If the foam is too dense or too thick, or not fully reticulated, the reagents can become cross contaminated or the tissue may not be fully infiltrated with the fluids because each fluid bath must fully clear and exchange from one fluid bath to the next.

[0069] Now referring to FIGS. 3C and 3D, assembly 10 is shown in which cassette 12 and lid 18 are in the second position. Pressing the center of lid 18 causes breakaway connections 36 to separate, allowing lid 18 to move from the first position towards the second position. When connections 36 are broken, continued pressure on the center of lid 18 causes retention tabs 38 to bear against tabs 20 and slide through retention slots 40 of frame 14. Downward movement of lid 18 and tabs 20, 38 causes tissue cassette 12 to move from the first position towards the second position. More particularly, because cassette retention tabs 20 and lid retention tabs 38 are aligned in slots 40, downward movement of lid retention tabs 38 causes downward movement of cassette retention tabs 20. Because slots 40 are tapered, the friction fit between slots 40 and tabs 20, 38 in the second position secures cassette 12 in the second position during the embedding and sectioning process. As best shown in FIGS. 3B and 3C, retention slots 40 include a bottom edge 46. When cassette 12 reaches the second position, edge 46 will prevent further movement of cassette retention tabs 20, and thus lid retention tabs 38, through slots 40. In the second position, tissue sample 44, a portion of cassette 12, and a portion of resilient structure 42 are staged to be sectioned in a microtome. While cassette 12 is shown to have a rectangular configuration, it will be recognized that cassette 12 may have alternative configurations. For example, a cassette may have a circular configuration. Because edge 46 limits the travel of cassette 12 into the second position, edge 46 assures that cassette 12 is staged to a predetermined depth independent of the configuration of cassette 12. The illustrated configuration of cassette 12, frame 14, and lid 18 is an improvement over current assemblies that require a complex lid adjustment procedure whereby the user must choose from a limited number of specific engagement distances between the lid and the cassette. The specific engagement distances were determined by preset tabs in the interior of the cassette basket that engaged and retained the lid. By utilizing a breakaway, rigid central staging lid coupled to a resilient structure according to an aspect of the present invention, the complex adjustment procedure for the lid is eliminated. It will be appreciated that other configurations and designs may be used to achieve similar purposes.

[0070] Because there are millions of procedures completed each year utilizing assemblies like these, embodiments of the present invention are designed for high production volumes and, consequently, are directed towards use in automated histopathology processes. One such process is automated embedding. An exemplary automated embedding machine (not shown) uses a motorized staging device 48 that pushes the cassette through the frame into the embedding mold 52, which is shown in FIGS. 3B and 3C. A staging device 48 may incorporate spring-loaded cylindrical fingers or feet which push the cassette through frame. The staging device 48 may be improved so that it is capable of cleanly severing breakaway connections 36 between peripheral portion 16 and lid 18 during the staging process. For example, tubular cutters may be axially positioned around the cylindrical fingers that align with connections 36 to cut them, which would be easier than breaking the connections 36 with shear forces alone.

[0071] In use, one or more tissue samples 44 are placed within the interior space or recess and, specifically, on bottom wall 12b of cassette 12 as shown in FIG. 3A. Tissue sample 44 is sized and oriented in cassette 12 according to the required section plane desired by the pathologist for each tissue sample 44. Peripheral portion 16 is then closed and snapped into place such that resilient structure 42 (e.g., foam) bears against and traps tissue sample 44 against bottom wall 12b in the desired orientation as shown in FIG. 3B. Resilient structure 42 may deform to create a three dimensional space that receives tissue sample 44. The force of resilient structure 42 against tissue sample 44 should be enough to immobilize tissue sample 44 but not enough to induce artifacts in tissue sample 44. At this point, assembly 10 with the trapped tissue sample 44 may be subjected to a conventional tissue processing operation that uses vacuum, heat and chemicals to remove the interstitial fluids within the tissue and replace those fluids with a hardenable material, such as molten paraffin. As mentioned above, during these processing steps, the porous nature of the foam or other resilient structure 42 allows the fluids to reach and fully infiltrate into tissue sample 44. In addition, resilient structure 42 traps tissue sample 44 flat against bottom wall 12b without leaving artifacts or markings on the tissue that might interfere with subsequent analysis under a microscope. It will be appreciated that different types of resilient cellular materials may be chosen based, for example, on the type of tissue to be processed and analyzed. For example, small mucosal tissue samples may be held and processed with success using the T-50 foam discussed above, while other types of tissue, such as fatty tissue, may be better served by another type of resilient cellular material. As another example, larger tissue samples may require retention structure that operates well over a large surface area.

[0072] It will also be appreciated that the processing steps may take place before assembling tissue cassette 12 with frame 14. After the tissue processing is complete, lid 18 may be separated from peripheral portion 16 whereby cassette 12 may be moved to a second position as shown in FIG. 3C exposing a portion of cassette 12 below the bottom edge 46 of frame 14.

Cassette 12 and frame 14 are then placed into a suitable mold 52 and embedded in paraffin 50. Cassette 12 and/or frame 14 may include machine- readable indicia allowing a machine to determine the type and size cassette 12 being used and to make an appropriate decision as to which mold to place the cassette 12 in for embedding. As shown in FIGS. 3D, the entire assembly 10 including the exposed portion of cassette 12 is embedded within a hardened block of paraffin wax 50. The mold 52 may generally follow the contour of the bottom 12b of cassette 12, although the portion of the mold surrounding cassette 12 is preferably square as opposed to round. This assists with the subsequent production of ribbon slices, as shown in FIG. 4. This portion of the procedure may therefore be similar to that disclosed in the above-incorporated patent and patent applications. As discussed therein, and with reference to FIG. 4, frame 14 is then used as a fixture for mounting the embedded assembly 10 in a microtome 54. The necessary number of slices 56 are taken of the exposed underside until enough sections, similar to those shown in FIG. 5, are taken and appropriately mounted on a microscope slide, stained and cover slipped.

[0073] Another method (not shown) of loading tissue sample 44 in assembly 10 is possible. First, peripheral portion 16 is detached from frame 14, which is set aside. Tissue sample 44 is placed onto resilient structure 42, and then frame 14 is installed on top of lid 18. When frame 14 is installed on top of peripheral portion 16, latches 24, 26, 28 of peripheral portion 16 engage with openings 30, 32 and flange 34, respectively, of frame 14. In this manner, peripheral portion 16 is secured to frame 14. Assembly 10 may then be positioned in its usual upright position while resilient lid 18 remains coupled to frame 14 and structure 42 secures tissue sample 44 to bottom wall 12b of cassette 12. This technique can be especially useful for processing an array of small tissue samples because of the easy access to resilient structure 42. In addition, resilient structure 42 may have tissue specific orientation or holding alignment features to facilitate orientation of very specific types of tissue samples. For instance, resilient structure 42 may be made from a gel material having specific cavities or grooves that accept small, hard to orient tissue samples. Such small tissue samples may be, for example, optic nerves from mice or thin arterial structures that must stand up on end perpendicular to the sectioning plane.

[0074] Cassette 12 may be formed from a sectionable plastic, such as perfluoroalkoxyethylene (PFA), in accordance with the above-incorporated patents and patent applications. The material forming cassette 12 may be at least translucent so as to be non-distracting during tissue analysis. Frame 14, including peripheral portion 16, and lid 18 may be formed from a more rigid, less costly plastic, such as acetal. Acetal is far easier to mold in large quantities or in multi-cavity injection molds. Unlike previous cassettes used during tissue analysis, lid 18 may be formed from a more cost-effective plastic that is different from the plastic used to form cassette 12. For instance, lid 18 may be formed from acetal. In this regard, the volume of FEP/PFA used in the assembly 10 is minimized, which is beneficial for cost reasons. As will be appreciated from FIG. 2, cassette 12 may be molded separately from the frame 14 and then inserted into the frame 14 with a suitable friction or "snap" fit.

Further, when cassette 12 and frame 14 are made of materials with significantly different melting temperatures, they can be co-molded or insert molded in an injection mold machine. In this case, there would be breakaway connections (now shown) similar to the connections 36 formed between the peripheral portion 16 and the lid 18.

[0075] In the co-molding or insert molding process, cassette 12 may be molded first, using the material having a higher melting temperature. Frame 14 and lid 18 may then be molded around cassette 12 tying them together in a single unit. Because frame 14 and lid 18 are made of plastic having a lower melting temperature than the plastic forming cassette 12, this step of the process will not melt cassette 12. In that way, through robotic assembly, cassette 12 can be molded with frame 14 surrounding it resulting in a processing container that the customer does not need to assemble from parts. Additionally, using such a molding process creates a secure, one piece assembly for shipping and handling. By combining the cassette and frame into a single piece prior to the customer receiving them, the assembly arrives as a single piece ready to load with tissue. This is advantageous over prior assemblies where the user was required to assemble the components before loading the tissue. Further, by surrounding the cassette by a dimensionally stable frame material, the integrity and shape of the cassette are maintained during shipping.

[0076] Referring now to FIGS. 7, 8 and 9, an assembly 100 is shown and constructed in accordance with another illustrative embodiment of the invention. Like elements of structure and function in the embodiments to follow are denoted with like reference numerals to those previously shown and described. The assembly 100 includes a tissue sample cassette 1 12 including a body 1 12a with an interior or recess 1 12b carried within a frame 1 14, which includes a peripheral portion 1 16. A lid 1 18 is separably coupled to the peripheral portion 1 16 and the peripheral portion 1 16 generally includes an interior 1 16a defined between surrounding walls 1 16b. The lid 1 18 is sized and configured to fit in the interior 1 16a and is separably coupled to at least one of the surrounding walls 1 16b. The frame 1 14 generally includes an interior 1 14a defined between surrounding outer walls 1 14b and the cassette 1 12 is sized to fit within and, after detachment from the frame 1 14, move within the interior 1 14a of the frame 1 14 between at least first and second "staging" positions, as discussed in the above-incorporated patent and patent applications and for the same purposes.

[0077] More specifically, in this embodiment, the entire cassette and frame assembly may be formed in a single molding process from a single material. This material may, for example, be a polyethylene-polypropylene blend or any other suitable material that has sufficient rigidity to provide the necessary support and resist warpage during storage and shipping, but which allows the cassette body 1 12a to be sectioned as disclosed in the above- incorporated patents and patent applications. Alternatively, the lid 1 18, frame 1 14, cassette 1 12 and/or portions thereof may be formed from different materials depending on factors such as cost and functionality. Of course, the molding process may have separate molding steps. However, as compared to previous embodiments, a single material embodiment has various advantages, such as cost advantages associated with a simpler molding process, and the use of a single, cost efficient and yet functional material. This embodiment further shows the use of flexible fingers 120 as the resilient, biasing structure extending from an interior surface of the lid 1 18 for engaging with a tissue sample or samples 1 12 (FIG. 10A) as will be discussed below. The peripheral frame portion 1 16 is coupled to the remainder of the frame 1 14 by a hinge 122. As best shown in FIG. 9, the lid 1 18 is coupled to the peripheral portion 1 16 with material "bridges" or breakaway connections 126 that are broken as the user depresses on the lid 1 18 during the staging process as will be discussed below. The lid 1 18 further includes "cutters" 130 that align with bridges or breakaway connections 132 that secure the cassette body 1 12a to the frame 1 14 as also shown in FIG. 9. As the user depresses the lid 1 18 and breaks the lid 1 18 away from the peripheral portion 1 16 at connections 126, these cutters 130 cut through or break the bridges or connections 132 that retain the cassette body 1 12a to the frame 1 14. It will be appreciated that the cutters 130 do not need to be sharp, but are at least meant to concentrate force on the thin connections 132. FIGS. 10A and 10B illustrate the respective open and closed positions of the cassette lid 1 18 and peripheral portion 1 16. FIG. 10B illustrates the resilient fingers 120 used to retain a tissue sample(s) 124 against the bottom wall 1 12c of the cassette 1 12. FIG. 10C illustrates the staging movement of the cassette 1 12 between the upper position (not shown) and the lower position that is within a mold 140.

[0078] In FIG. 10C, the bridges or connections 126 previously discussed have been broken and, thus, the lid 1 18 is retained against the upper peripheral surface of the cassette body 1 12a. In the second position, or lower position, the cassette body 1 12a is exposed below the bottom of the frame 1 14 for allowing the cassette body 1 12a and the tissue sample 124 to be sectioned in a microtome 54 (FIG. 4) while the frame 1 14 is held in the microtome chuck, as previously described. As further shown in FIG. 10C, the frame 1 14 is frictionally held within the mold 140 by being retained against a resilient seal member 142 coupled with the mold 140. FIG. 10D illustrates the process after the step of filling the mold 140 with an embedding material, such as paraffin 150, and allowing the paraffin 150 to solidify into a block that encases both the sectionable cassette 1 12 and the tissue sample 124 held within the cassette 1 12 recess or interior 1 12b. As fully described in the above-incorporated patents and patent applications, and above, this solidified block 150 is then sectioned in a microtome 140 (FIG. 4) and the thin, ribbon-like sections 56 are placed on microscope slides (not shown) for pathological diagnoses.

[0079] FIGS. 1 1A, 1 1 B and 1 1 C better illustrate the construction and use of the breakaway connections 126, 132 and cutters 130 that are associated with the cassette 1 12 and the frame 1 14. Specifically, the cutters 130 align with the bridges 132 that connect the cassette body 1 12a to the frame 1 14 and, as shown in FIG. 1 1 B, these cutters 130 when depressed downwardly will cut through or help break or shear the frangible bridges or connections 132 thereby separating the cassette 1 12 from the frame 1 14. At about the same time, the frangible bridges of material 126 that hold the cassette lid 1 18 to the peripheral portion 1 16 break and the lid 1 18 then travels with the cassette body 1 12a from the first position (not shown) to the second, staged position, illustrate in FIG. 1 1 C. FIGS. 12A and 12B illustrate another perspective showing the bridges 132 and the use of the cutters 130 to break the bridges 132 and allow movement of the cassette 1 12 and the cassette lid 1 18 from the first position shown in FIG. 12A to the second position shown in FIG. 12B.

[0080] FIGS. 13 and 14 illustrate another illustrative embodiment of a device 100' that is very similar to the embodiment shown and described with respect to FIGS. 7 through FIGS. 12A and 12B. Like reference numerals in FIGS. 13 and 14 refer to like structure shown and described in the previous embodiment. Therefore, further explanation of previously described structure is not necessary. In this embodiment, the resilient fingers 120 depicted in the previously embodiment have been replaced by pads 160 that are coupled to an under side of the lid 1 18 by resilient legs 162. Again, this entire cassette and frame structure, including the pad members 160 and legs 162 may be molded out of a single material and within a single mold, thereby greatly simplifying the manufacturing process. Alternatively, two or more of these components may be co-molded or insert molded. As shown in FIG. 14, the resilient pad members 160 are used to retain the tissue sample or samples 124 against the bottom surface 1 12c of the cassette 1 12, thereby holding the tissue sample or samples 124 in a desired orientation and flatly against the inner bottom surface 1 12c of the cassette interior 1 12b. The legs 162 that connect the pads 160 to the underside of the cassette lid 1 18 may slightly rotate and bend as the pads 160 engage the tissue sample 124 when the lid 1 18 is closed. This stabilizes and holds the tissue sample(s) 124 during tissue processing and embedding.

[0081] FIGS. 15, 16A and 16B illustrate yet another illustrative embodiment of a device 100" that is very similar to the embodiment of FIGS. 13 and 14. Like reference numerals again refer to like elements of structure and function as previously described and, therefore, need not be described again. In this embodiment, the only difference relative to the embodiment in FIGS. 13 and 14 is that the resilient pad members 160' have been changed in shape and slightly in structure to be more rounded and for the leg members 162' to be resilient and twistable similar to springs to better engage and hold one or more tissue samples 124 within the cassette interior 1 12b and against the interior bottom surface 1 12c of the cassette 1 12 as shown in FIG. 16B. [0082] Now referring to FIGS. 17, 18, 19A and 19B, another illustrative embodiment of a device 100"' is shown and again may be formed from a single material and within a single mold, as will be appreciated from the description to follow. Again, like reference numerals in this embodiment refer to like elements of previous embodiments. In this embodiment, like the embodiment shown and described with regard to FIG. 7 through FIG. 12B, the cassette body 1 12a is connected to the interior peripheral surfaces of the frame 1 14 by breakaway material bridges or connections 132. The lid 1 18' of the cassette 1 12, however, is designed to fit and latch within the cassette body 1 12a and to be depressed downwardly into the interior 1 12b of the cassette body 1 12a and against one or more tissue samples 124 therein to retain the tissue sample or samples 124 against the interior bottom surface 1 12c of the sectionable cassette 1 12. The "latching" may simply be a friction fit. The material bridges 132 between the cassette body 1 12a and the frame 1 14 are designed to be thin and easily frangible as the cassette 1 12 is staged from the first position to the second position, shown in FIG. 19C. A user or a machine may depress the cassette lid 1 18' into the cassette body 1 12a as also shown in FIG. 19C and the cassette lid 1 18' may snap between two detents 170, 172 as also shown in FIG. 19C. A hinge 176 connects the lid 1 18' to the frame 1 14 and has a length such that the cassette lid 1 18' may extend downwardly into the cassette body 1 12a as the cassette body 1 12a is staged from the first position shown in FIG. 19B to the second position shown in FIG. 19C. The structure and function of this illustrative flexible and elongated hinge structure 176 is shown better in FIGS. 20A, 20B and 20C.

[0083] FIGS. 21 through 24B illustrate yet another embodiment of device 200. Again, this device 200 may be formed from a single material and within a single mold, as will be appreciated from figures and the description to follow, or as in any of the previously described embodiments, may be formed from different materials using other molding techniques such as co-molding or overmolding. Again, like reference numerals in this embodiment refer to like elements of structure and corresponding function as described with regard to previous embodiments. Therefore, further description of such elements is not repeated here. Elements having one or more prime (') marks are slightly modified from prior, corresponding elements, as will be described. In this embodiment, like the embodiments previously shown and described, the cassette body 1 12a is connected to the interior peripheral surfaces of the frame 1 14 by breakaway material bridges or connections 132. The lid 1 18" of the cassette 1 12 includes cutters 130 but is also designed to latch to the cassette body 1 12a using a plurality of latches 202. Like previous embodiments, the lid 1 18" is separable from the peripheral portion 16 of the frame 14. Another difference between this embodiment and previously described embodiments having "resilient structure" for engaging tissue samples within the cassette 1 12, is that the resilient structure comprises a plurality of linear fingers 204 which may be straight and distally tapered as shown best in FIG. 23A. As

alternatively shown in FIG. 23B, the distal ends 204a of the fingers 204 may instead be curved to provide more surface area engagement with one or more tissue samples and a "softer" engagement that is less likely to damage the tissue sample. Another difference between this embodiment and previously described embodiments relates to the method and structure for positioning the cassette 1 12 and lid 1 18" within the frame 1 14. In this regard, as best shown in FIGS. 24A and 24B, each corner of the cassette lid 1 18" engages with a cassette positioning element 210 that is formed as part of the interior corner of the frame 1 14. The cassette positioning elements 210 are flexible and hollow such that as the corners of the lid 1 18" pass by the cassette positioning elements 210 they deform the cassette positioning elements 210 and ultimately "snap" below the cassette positioning elements 210 as shown, for example, in FIGS. 22B and 24B. This retains the cassette 1 12 and lid 1 18" in the second position, and ready for embedding and subsequent microtome sectioning, as previously described.

[0084] While the present invention has been illustrated by the description of specific embodiments thereof, and while the embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. The various features discussed herein may be used alone or in any combination within and between the various embodiments. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of the general inventive concept.